The joystick axes output a double between -1 and 1. Victors and Jaguars conveniently accept a double value between -1 and 1 as an input.
Relays can be set to kForward, kReverse, or kOff (or kOn, but that doesn't seem to matter here).
So you need to write some code that translates from [-1, 1] to [kForward, kReverse, kOff].
All you need to do is write an if...else statement that checks if the joystick axis is pushed forward, backwards, or is in the center. In other words, is the axis <0, >0, or ==0 (note that you might not want to check if it is exactly zero, since the tiniest bit of movement would make your motor move - you probably want a threshold so that if the stick is within, say, .1 of 0, just call it zero).
EDIT: Aww, Dave - he was getting so close!
